(a) Field of the Invention
The present invention relates to a method and an apparatus for controlling regenerative braking of a hybrid electric vehicle, and more particularly, to a method and an apparatus for controlling regenerative braking of a hybrid electric vehicle that adjust a regenerative braking torque by classifying as at least two or more regenerative braking modes and applying different regenerative braking slope based on each mode.
(b) Description of the Related Art
Generally, a hybrid electric vehicle is driven by an engine which generates torque from fuel combustion and an electric motor which generates torque from an electric battery. In other words, a hybrid electric vehicle has a power device comprised of an engine and a motor and is driven by appropriately using each power that has been generated by a combustion action of the engine and power that is generated by a rotation of a motor using electrical energy that is stored within a battery.
To improve fuel consumption, a vehicle using a power generation control as well as a hybrid electric vehicle uses regenerative braking technology. A regenerative braking system uses a portion of a braking force for power generation upon braking of a vehicle, charges generated electrical energy in a battery, and uses a portion of kinetic energy by a driving speed of a vehicle as energy necessary for driving a generator. Accordingly, a regenerative braking system simultaneously implements reduction of kinetic energy and generation of electrical energy. In addition, a hydraulic pressure braking system which generates braking force based on hydraulic pressure is provided within the hybrid electric vehicle. Since the regenerative braking is generated by only a wheel connected to the motor, regenerative braking cannot satisfy a braking request of a driver.
Therefore, the hydraulic pressure braking and the regenerative braking are performed simultaneously in the hybrid electric vehicle based on an operation of a brake pedal. However, there is a problem caused by a difference of reactivity since reactivity of the regenerative braking system is rapid, on the contrary, reactivity of hydraulic pressure braking system is slow.
A traditional hybrid electric vehicle uses a slope of a straight line while calculating a regenerative braking amount to generate a shock or a deceleration change based on the difference of reactivity between the regenerative braking system and the hydraulic pressure braking system. Moreover, when the slope is decreased to minimize the shock or the deceleration change, the regenerative braking amount also decreases which results deterioration of fuel efficiency.
The above information disclosed in this section is merely for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.